IPv6 Full Expanded Form Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching ipv6 full expanded form, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# IPv6 Full Expanded Form
# ReDoS-safe | RegexVault — Web & Network > IPv6

import re

ipv6_full_expanded_form_pattern = re.compile(r'^[0-9a-fA-F]{1,4}(?::[0-9a-fA-F]{1,4}){7}$')

def validate_ipv6_full_expanded_form(value: str) -> bool:
    return bool(ipv6_full_expanded_form_pattern.fullmatch(value))

# Example
print(validate_ipv6_full_expanded_form("2001:0db8:85a3:0000:0000:8a2e:0370:7334"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > IPv6 category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

This matches only the fully expanded form. Does not accept :: compression. Each group can be 1–4 hex digits (leading zeros optional within group).